1. Technical Field
The present invention relates to an apparatus for controlling a multi-winding rotary machine including an armature formed of a plurality of winding sets.
2. Related Art
In a three-phase double winding rotary machine, which is a rotary machine having two sets of three-phase windings, an interfering voltage proportional to a derivative of a current flowing through one of the two three-phase winding sets is induced in the other one due to magnetic coupling between the two three-phase winding sets, which may reduce responsiveness of a current control system for an electrical motor. To overcome this drawback, there has been proposed in Japanese Patent Application Laid-Open Publication No. 2003-153585 an apparatus for controlling such a three-phase double winding rotary machine, which is configured to control inverters electrically connected to the respective three-phase winding sets to thereby control the rotary machine. More specifically, command voltages to be applied to the respective three-phase winding sets are corrected by using the interfering voltages proportional to derivatives of currents flowing through the respective three-phase winding sets. Such a technique can prevent reduction of responsiveness of the current control system, thereby reducing ripple components of the currents flowing through the respective three-phase winding sets. This can reduce torque ripple of the electrical motor.
The interfering voltage induced in each three-phase winding set due to magnetic coupling between the two three-phase winding sets includes not only the set forth interfering voltage proportional to the derivative of the current, but also an interfering voltage proportional to a rotation speed of the electrical motor. When the rotation speed of the electrical motor is high or varies with time, the interfering voltage proportional to the rotation speed of the electrical motor may reduce responsiveness of the current control system, which may lead to an increase in torque error, where the torque error is a deviation of an output torque of the electrical motor from its command torque.
In consideration of the foregoing, it would therefore be desirable to have an apparatus for controlling a multi-winding rotary machine, capable of properly increasing responsiveness of the current control system for the multi-winding rotary machine.